Photomicrograph demonstrating that the glycogen granules in superficial lobules (SU). C: capsule stain more intensely than those in lobules located deeply (DU). PAS. X40. 

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... sinusoids. Khatim et al., (1985), on the other hand, stated that, the hepatocytes of camel were characterized by the presence of numerous cytoplasmic inclusions (vesicles, vacuoles) that might occupy most of the cell, and appeared larger than the nuclei, although their significance was unknown. Although there are some quantitative anatomical data on the liver of certain species of animals: Sheep (Gooneratne et al., 1980), Rainbow traut ( Salmo gairdneri ) (Hampton et al., 1989), rat (Zhao et al., 1993), Black Bengal goats and Chotanagpuri sheep (Massarat et al., 1996) and man (Ludwig et al., 1998), comprehensive morphometric data on the liver of the dromedary camel is virtually lacking. The conflicting reports about the distribution of glycogen and lipid, and the absence of any reference, in the literature available to the authors, of the relative volumes of the components of the dromedary liver, the present study was undertaken as prerequisite to understanding structure- function relationship of the liver of the camel. A total of ten livers were collected from slaughter-houses. Specimens were obtained from both sexes at different ages. The livers used for this study were all apparently normal, and each liver was taken as soon as possible following slaughtering of the animals. Thin slices of tissue (about 1 cm long and 5 mm thick) were taken from the right, left, quadrate and caudate lobes of the liver and from the portal fissure. For detection of glycogen, tissues were fixed either in Gender's Fluid at 0- 4 ̊C, or in 10% formalin . After fixation, the tissues were processed by routine histological techniques (Culling, 1974; Drury and Willington, 1980). The specimens were dehydrated in ascending grades of ethanol, cleared in xyline, and embedded in paraffin. Tissue blocks were then cut at a thickness between 5 and 7 μm and mounted onto glass slides pre-coated with albumin. The sections were further cleared in xyline and rehydrated in descending grades of ethanol, washed in water and stained with Best ’ s carmine or PAS. Control sections for glycogen were treated with 0.1% diastase or saliva for 30 min, at 37 ̊C, or at room temperature (Drury and Willington, 1980). For demonstration of lipid droplets, tissue blocks were fixed either in 10% formal calcium or 10% formal saline for 24 hours, then frozen in liquid nitrogen (- 197 ̊C) before being cut in the cryostat at a thickness between 10 and 15 μm. The slides were rinsed in 10% formalin to fix the sections on the slides. Then they were stained by Oil Red O-triethyl phosphate method (Drury and Willington, 1980). Control sections were treated with acetone at -20 ̊ C for 20 minutes to extract lipid (Pearse, 1965). For morphometric study, five normal livers were used. Volumes of fresh livers were determined by water displacement method (Aherne and Dunnill, 1982). Five thin slices were taken randomly from the right, left, quadrate and caudate lobes and from the portal fissure of each 1iver. Samples were processed for routine histological technique and stained with Haematoxylin and Eosin according to Culling (1974). A total of twenty five sections from five livers were used for morphometric analysis. A grid with 100 points, fitted in ×12.2 eye piece, was used to determine the volume densities of the main components of the liver (Aherne and Dunnill, 1982). These components are: hepatocytes, blood vessels, connective tissue, interlobular bile ductules and ducts. Each section was entirely analyzed, field by field, giving a range of 15-33 fields per section. The sufficiency of the number of points necessary to count for each component in order to keep the standard error below 5% was confirmed by the plot of Weibel (1963). The absolute volumes of the components of the liver were calculated from the volume densities (V v ) of the component, and the total volume (V) of the fresh liver. The statistical analysis of the data obtained by the point-counting was restricted to the calculation of the mean and standard deviation (Weibel, 1963). The distribution of glycogen in the cytoplasm of the hepatocytes appeared either as scattered fine granules or as small closely packed granules (Fig. 1). The glycogen content of hepatocytes varied from cell to cell. In some cells, the glycogen clumps had a perisinusoidal arrangement (Fig. 1). Following the use of Best ̓ s carmine method, the distribution of glycogen was uniform throughout the lobule (Fig. 1). However, the hepatic glycogen showed a distinct lobular pattern when PAS method was used. Within the lobule, the peripheral hepatic cells showed intensely stained masses of glycogen (Fig. 2). The area of the peripheral zone varied among lobules, depending on the amount of glycogen. In some lobules, the mass of glycogen appeared as a thin strand while in other lobules it was thick (Fig. 2). The lobules located at subcapsular region of the liver had a larger amount of glycogen compared to the lobules present away from the capsule (Fig. 3 and 4). It was clearly distinguished that the glycogen content of the liver varied from animal to animal, and among lobes within the same liver. The present study showed that, the left and quadrate lobes contained more glycogen than the right and caudate lobes. In these two lobes, the hepatocytes of the middle and peripheral zones of some lobules contained larger amount of glycogen than the central zones (Fig. 5). The current investigation showed that, the hepatocytes of the liver of the camel were characterized by the presence of numerous cytoplasmic vacuoles in ordinary histological slides (Fig. 6). The used of the modified staining method of Lillie Ashbrun's Isopropanol Oil Red for lipid demonstrated a moderate to a large number of lipid droplets in the cytoplasm of the hepatocytes. The lipid droplets were distributed all over the lobule but they had tendency to be concentrated in the cells located at the peripheral zone than in the cells of the central zone (Fig. 7). The lipid droplets varied in size, and located in the cytoplasm of hepatocytes adjacent to the sinusoids (Fig. 8). Tables (1-3) were showing the results of the morphometric analysis. The mean volume of the fresh liver of the camel ( Camelus dromedarius ) 3 was about 6692 cm . The morphometric data showed that, the mean percentages of the volume densities of the main components of the liver were: the hepatocyts (79.60±3.42), the blood vessels and hepatic sinusoids (12.38±2.4), the connective tissue which included the capsule, trabeculae, and portal canals (7.70%±1.77), the bile duct and ductules (0.30%±0.13) (Tables 1 and 2). From the morphometric analysis, the left hepatic lobe contained the largest amount of interlobular and intralobular connective tissue (9.7%), while the left lobe and quadrate lobe presented a high percentage of blood vessels (14.0%) (Table 3). The present investigation showed that, the glycogen content of the dromedary liver as a whole was variable, varying from cell to cell, and from lobule to lobule. These observations confirmed the earlier findings of Bahgat et al., (1965) and Lalla and Drommer (1997) in the camel. The distribution of the glycogen indicated a distinct lobular pattern where the hepatocytes located at the peripheral zones of all lobules and both peripheral and intermediate zones in some lobules showed more intensely- stained masses of glycogen compared to the hepatocytes localized at the centrolobular zones. This confirmed earlier observations in the liver of man (Leeson and Leeson, 1970; Kudryavtseva et al., 1996). However, Shahien, et al. , (1977) claimed that, in the dromedary liver, in some lobules, glycogen is concentrated more in the hepatocytes located at both peripheral and central zones than in other lobules, in which glycogen is evenly distributed. In the rat liver, the hepatocytes of the central zone showed a higher concentration of glycogen than in the other zones (Van Noordeen et al., 1994). The conflicting reports about the distribution of glycogen may be explained by stating that glycogen is a very labile substance. Another probable explanation is offered by Jungerman and Kietzmann (1996) who claimed that, although the liver tissue was uniform on the level of histology, it was heterogeneous on the level of morphometery and histochemistry. This heterogenity was due to the blood supply. Cells located in the upstream or periportal zone differ from those in the downstream or central zone in their equipment with key enzymes, translocator, receptors and subcelluar structures and therefore, had different metabolic zonation. In this study, the glycogen content of the liver varied from animal to animal, and among lobes within the same liver. The left and quadrate lobe contained more glycogen than the right and the caudate lobes. This result confirmed the explanation made by Scheiff (1931), who attributed the variation in the glycogen content of the different parts of the liver to differences in the blood supply of the various lobes. Interestingly, the present morphometric findings of the dromedary liver showed that, the left and quadrate lobes had a volume of blood vessels higher than that in other lobes. In contrast, Corrin and Aterman (1968) stated that, glycogen content in the liver of rats, fasted and re-fed at various intervals, is normally uniform in distribution; they attributed the variations in the content of glycogen between lobes, reported by other authors, to the techniques of sampling and determination. On the other hand, Shahien et al., (1977) claimed that, the histochemically demonstrable glycogen showed a marked dependence on food intake. Yang and Makita (1998) reported that, with decreasing weight of livers, the glycogen content decreases in fasting group of Japanese monkeys. In all mammals, lipid droplets are few in normal hepatocytes, but may increase in disease, after consumption of alcohol, or toxic substance (Bloom and Fawcett, 1986). Abdalla et al., (1971) ...